A total of 13 case reports describing AIAI have revealed several characteristic features of the disease. Patients often have recurrent episodes of abdominal complaints and are sometimes given an alternative diagnosis with occasional surgical intervention. The time of diagnosis varied from a few hours to seven years following the initiation of ACE inhibitor, with over 75% of patients (10 of 13 patients) having a delayed diagnosis (two months or longer), and was independent of the dose of ACE inhibitor. This was likely due to a delay in presentation and/or diagnosis. Patients reported a chronic use of ACE inhibitors associated with recurrent gastrointestinal symptoms and multiple episodes of acute exacerbations. Gastrointestinal symptoms in patients taking ACE that cannot be explained by other more common causes should prompt physicians to consider AIAI, irrespective of the duration of therapy. In addition, several patients had prior episodes of angioedema involving the face and/or oropharynx. As such, a diagnosis of ACE inhibitor-induced angioedema of the face and/or oropharynx does not preclude the possibility of AIAI.
Radiological studies (contrast-enhanced CT and/or ultrasonography) are instrumental in documenting the location and extent of bowel edema and ascites and their resolution. The characteristic radiological findings of AIAI are similar to those of HA and include segmental thickened bowel wall (small and/or large intestine), narrowed lumen, and prominent and thickened valvulae con-niventes, often with the presence of ascites. An extensive history and series of investigations are essential to rule out allergic, C1-INH deficiency (hereditary and acquired), inflammatory (including infectious), vascular (including lymphatic blockage and hemorrhage), and other miscellaneous causes of ascites and bowel edema. Documented causes of angioedema of the intestine include the use of ACE inhibitors (AIAI), dual inhibitors of ACE and neutral endopeptidase (eg, omapatrilat), allergic reactions to drugs, food and radiographic contrast agents, HA with and without the use of ACE inhibitor and malignancy-associated paraneoplastic manifestation.